Questions and answers on the essentials of medical chemistry / By Lawrence Wolff.

  • Wolff, Lawrence.
Date:
1888
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Licence: Public Domain Mark

Credit: Questions and answers on the essentials of medical chemistry / By Lawrence Wolff. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    Hydrogen. What is hydrogen, and what its properties ? A colorless, odorless, tasteless elementary gas, rarely found free in nature. Symbol H, atomic weight 1, valence1, molecu- lar weight 2; one liter at 760 mm. pressure and 0° C. weighs 0.08958 grams = 1 crith. It is combustible, but not a supporter of combustion. A mixture of H and O will explode violently when lighted, forming water. How can it be demonstrated that it is lighter than air? A balloon or soap-bubble filled with it will rapidly ascend. It can be readily transferred by pouring it from one inverted vessel into another from below upwards, displacing the air in doing so. What is its diffnsibility ? It is highly diffusible, penetrating through porous bodies with ease, and diffusing through membranes. Is hydrogen under ail circumstances and conditions a gaseous body? It can be reduced to the liquid state by cooling to —140° C, and under a pressure of 600 atmospheres. It then resembles a steel-blue, non-transparent fluid, somewhat like mercury, and upon evaporation even solidifies. How can the formation of water by the union of H ard 0 be proven ? If a flame of hydrogen is allowed to burn in a cool glass cyl- inder, this will soon be found covered with clew. How can hydrogen be prepared ? By electrolysis of water, by the action of some metals on water, and by the action of zinc or iron on sulphuric or hydro- chloric acid. What is the result of the electrolysis of water in the Hoff- mann's tubes, and how is the presence of H proven? When acidulated water is subjected to electrolysis, the H will accumulate in the tube containing the negative electrode, the O